{
  "correct_letter": "D",
  "correct_formula": "y = h + x·tanθ - g·x² / (2·v_0²·cos²θ)",
  "annotation": "Environment: g=-9.81, F_drag=0.0\nGround: e = 0.4\nCopperSphere: d = 2.0, e = 0.45, h = 2.0, v_0 = (0.0, 10.0, 6.0)",
  "choices": [
    "a_n = v² / ρ",
    "v_x(t) = v_0·cosθ · e^(-g·t/v_0)",
    "T = 2π·√(L/g)",
    "y = h + x·tanθ - g·x² / (2·v_0²·cos²θ)"
  ],
  "correct_index": 3,
  "physics_type": "Projectile",
  "seed": "Projectile|benchmark/projectile/10"
}